3-phase electrical panel for transformer testing

                                           3 PHASE ELECTRICAL PANEL FOR TRANSFORMER TESTING RATING UPTO 2.5 MVA 33KV/11KV TRANSFORMER        
 This panel is conecting of 4  parts     –
1. Incoming panel   2. OC and full load current  3. DVDF test  4. HV test                                                                                                                                                                                                    
                          It is power supply panel.Incoming ACB(air circuit breakers) of 320 amp connected with the main panel of the factory.first outgoing is 250  amp ACB(air circuit breakers) connected with the variac of 440 volt 200 amp rating.seconed outgoing is of 100 amp MCCB (Moulded Case Circuit Breaker) connected with variac of 440 volt 50 amp rating.third circuit is kept for auxiraly power supply of the panel.
                                                            open circuit test is carried out for measuring iron losses and full load current test is carried out for determining for total losses including iron loss.3 phase 440 volt 200 amp variac gives supply to booster transformer.Tapping of booster transformer is taken 1100 volt ,2200 volt and 3300 volt .Between variac of 200 amp and booster transformer capacitor bank of maximum 200 kvar is inserted in the binary arrangement  to maintain stability of supply and for improvement of power factor. Tapping of booster transformer is changed manually according to need  i.e. for testing of transformer 11kv/0.43kv , 22kv/11kv and 33kv/11kv.
                                                                  this test is carried out for checking insulation sustainability of transformer as it must sustain on applying  866 (double voltage)voltage .there is no other purpose for doubling the frequency but to ensure that iron looses should  not increase abnormally.If voltage is doubled and frequency is kept same iron looses will be abnormaly high causes heating of core of transformer.this set consisting of 20HP squirrel cage induction motor.which is used as prime mover and operated through star  delta starter.
generatior is specially designed for 3-phase ac winding either stator or rotor is used as primary/secondary.this is wound type stator and rotor.seperate supply is given to primary through 440 volt 50 amp  at 50  hz variac .output of generator is applied on transformer under test. primary poles of secondary is double then primary . 
transformer under test having open.secondary voltage impressed on transformer first it is increased to 1/3 rating then full voltage rating for 60 sec. period.dimmer is controlled through panel.Rating of DVDF is 50kva.
HV TEST (high voltage test ) –
                                       this test is carried out on transformer for high voltage.normally 2.5 times voltage is applied .HV transformer voltage is increased through taking out supply from 2-phases of dimmer .this dimmer is motor operated and control through panel.Rating of HV transformer is 80kv , 200mA.dimmer rating is 440volt 50amp.

(Updated : January 24, 2018)